Category Archives: New Mexico

Prehistoric Trackways National Monument

Tiny tracks from 280 million years ago are preserved in red siltstone.

Tracks in the Rocks

Mountains are nature’s mystery novel. Captured in layers of rock are stories about time, about life, about death. As I pass the Robledo Mountains just northwest of Las Cruces, New Mexico, I ignore the dry, sparsely vegetated cover, knowing an extraordinary story awaits me within the rock of the Prehistoric Trackways National Monument.

The monument, managed by the Bureau of Land Management, is relatively new, so infrastructure consists of a few interpretive panels, two dirt parking lots, and a hiking trail that switches up the hillside. I called ahead and signed up for a guided tour—the best way to discover the secrets of the Robledos.

Colin Dunn, paleontologist with the Bureau of Land Management, shows us a rock loaded with fossils.Skip the Dinosaurs

On that bright, spring, Saturday morning, a small group of hikers gather around Colin Dunn, the BLM paleontologist. We’ve come to see the fossilized trackways of creatures that squelched through mud 280 million years ago. “We’re skipping the dinosaurs,” Colin says. “Mammals, flowers, birds. Just skip it.” These tracks were made by animals 60 million years before any flower bloomed or dinosaur roamed the earth.

The trackway eroding from the Robledo Mountains dates to the Early Permian. At that time, New Mexico was part of a single, massive continent known as Pangea. The rocks that surround us are sediments from a shallow, warm sea that lapped against a tropical shoreline.

Fragments of sea urchin spines and shells make a jumble of shell hash in a rock.Shell Hash

We hike up a dry creek bed. Colin stops to show us long, thin sea urchin spines, round disks of crinoids (sea lilies), flat colonies of bryozoan, and ridged shells of clam-like brachiopods. These fossils create a layer of “shell hash”—a jumbled assortment of life in the Permian sea.

Tracks of a Dimetrodon are deeply impressed into red siltstone.


As we move inland from sea to shoreline, thick beds of red rock jut from the hillside. Colin scrambles to the first terrace. Crouched before a large, flat slab of siltstone he points out a series of tracks. About the size of my hand, the “palm” of each print is round and deeply impressed. The toes are long, thin, and sharply pointed.

“These are Dimetrodon tracks,” Colin tells us. Dimetrodon was the terrestrial terror of the Permian world. Lizard-like, with a bony sail fin down its back, the largest Dimetrodon was 13 ft. long and weighed 500 lbs. “This one was pretty small,” says Colin. “It was only about 100 lbs.”

Colin pulls a small rock out of his pocket. Clusters of three lines, each arranged like an arrow, cover the surface. “I was at White Sands and saw beetles making tracks just like this. I was totally geeking out!”

Walchia fronds from an upland forest washed downstream and pressed into the mud.Walchia Fronds

I am too. Fossilized bones fascinate me, but these tracks? Even better. Bones write the story of death. These footprints tell the story of life. I can picture an araeoscelid (go ahead and think lizard) scampering for cover, a beetle making its way across the mud, and the corkscrew twist of a worm as it drills a burrow. Raindrops dimple one rock; a mat of Walchia tree fronds from an inland forest is impressed on another. The fronds look like the potted Norfolk Pines I used to buy at the home improvement store.

By studying these tracks, paleontologists are unveiling twists to the mystery of Permian life. Initially, scientists believed Dimetrodon was a low-slung, lumbering thug. But the tracks—set close together and lacking belly scrapes or tail drag marks—suggest Dimetrodon was a sprinter rather than a plodder.

Colin tells me of petrified log jams and other track sites at the monument. He won’t share where they are though. “Have you heard of Fossil Cycad National Monument?” he asks. I shake my head, no.

“That’s the problem. Fossil Cycad had one of the world’s greatest concentrations of cycads. Then people came in and took them all. They shut down the monument because there wasn’t anything left to see. I don’t want that to happen here.”

I don’t either.

A sign at the monument tells of the trackway discovery and warns people not to collect rocks.

Getting There:

The Prehistoric Trackways National Monument is open to the public, but the best way to visit is with a knowledgeable guide. Tours to the Discovery Site are given once a month on Saturdays. Contact the Bureau of Land Management for more information.

To Learn More

Traces of a Permian Seacoast is a wonderful, beautifully illustrated book about the fossil trackways of Prehistoric Trackways National Monument. Purchase it from the link below to help support this blog!


Also posted in Chihuahuan Desert, Fossils, Geology, Travel

Places: Bitter Lake National Wildlife Refuge

Sandhill Cranes and geese head south

Sunrise at Bitter Lake National Wildlife Refuge, Roswell, New Mexico

The alarm goes off at 5 a.m. It’s cold, but I resist the urge to roll over and go back to sleep. I want to photograph Sandhill Cranes today, and they fly at dawn. I load up my camera gear and head for the Bitter Lake National Wildlife Refuge about 10 miles northeast of Roswell, New Mexico.

It’s a chilly 23F as I arrive, but the birds aren’t sleeping in either. As the sky brightens, they stir, murmuring and honking softly to each other. There are hundreds of Sandhill Cranes and thousands of Snow and Ross’s Geese in the shallow ponds of the refuge. Northern Shovelers, elegant Northern Pintails, and Mallard ducks disappear into the reeds as I stop to watch the sun come up.

The Sandhill Cranes and the geese take off, groups of birds bursting into flight all at once. They rise quickly into the air, to form V-shaped skeins as they head south.


Joseph R. Skeen Visitor Center overlooks wetlands

History of the Bitter Lake NWR

The Bitter Lake National Wildlife Refuge consists of 24,609 acres of wetlands along the Pecos River. Sinkholes, playa and oxbow lakes, freshwater springs, marshes, and man-made impoundments create a variety of aquatic habitats. Water in the desert is precious and tends to concentrate a broad range of species. Here, the wetlands support over 350 species of birds, 28 types of fish, and 110 dragonfly and damselfly species.

The refuge was established in 1937, three years after the passing of the Migratory Bird Conservation Act. The Act gave the federal government authority to purchase land for wildlife refuges. Although the refuge system was designed to protect upland game, mammals, and song, insectivorous, and ornamental birds; in the early years, waterfowl was clearly the focus.

By 1937, the region had suffered through 3 years of severe drought. Crops didn’t grow. The soil, no longer held in place by prairie grasses and forbs, blew away in billowing clouds. The once productive farmlands of the plains became known as the Dust Bowl. Waterfowl were hit hard by the drought, although overharvest by unregulated hunting and the draining of the wetlands to create farmland also took their toll. Early conservationists “Ding” Darling, Thomas Beck, and Aldo Leopold declared that waterfowl were in a state of crisis and called for an aggressive plan to create federal wildlife refuges.

Bitter Lake was chosen as one of the first wildlife refuges because of its location along the Central Flyway. The flyway—a great migratory route that cuts a swath across the middle of North America—is home to most of North America’s ducks and geese. Tens of thousands of birds move along the Flyway each year, flying north to breed in the summer and south for the winter.

Today, the refuge is known as much for its incredible diversity of dragonflies and damselflies as it is for its birds. The refuge also protects rare species including tiny snails the size of a glass seed bead, that cling to decaying leaves in the ponds. Shrimp-like amphipods—about the size of a lima bean—scoot across the bottom of sinkholes, and small fish dart for cover when a shadow crosses the pond surface. Many of these creatures can be found nowhere else in the world.


Exhibits explain this unique oasis in the desert.

The Joseph R. Skeen Visitor Center and Refuge Trails

Start your visit at the Joseph R. Skeen Visitor Center. There’s a 15-minute orientation film about the natural history of the refuge, beautiful interpretive exhibits, and even a tank of rare fish.

The back porch overlooks a large pond. With a pair of binoculars, you could sit out there all day and watch the American Coots and ducks going about their business. But to get the most from the refuge, jump back into your car and drive the Auto Tour or go for a hike.

Bitter Lake and the northern part of the refuge are closed to visitors, but the 6.5 mile Auto Tour loops around the ponds at the southern end of the refuge. The well-maintained dirt road is easily accessible by car. Along the loop,  several pull-offs guide you to overlooks where you can set up a scope and get a good look at the bird activity.

If you’d like to hike, five short hiking trails branch off from the Auto Tour road.  The trails lead into the uplands, around an oxbow lake, or out to observation blinds. They range in length from about 2 miles for the Oxbow Loop Trail to a short 0.2-mile butterfly trail.


Hundreds of Sandhill Cranes gather in the shallow ponds for the night.

Sandhill Cranes Gather For the Night

There’s something special at the refuge every season, but I was there in winter and specifically looking for the Sandhill Cranes and waterfowl that overwinter in this part of the Chihuahuan Desert. The Sandhill Cranes and light geese (a mix of Snow and Ross’s geese) leave the refuge at dawn to spend the day in nearby farm fields. At dusk, they return to the refuge to roost for the night in the shallow pond water where they’re protected from predators.

After my morning visit, I return to Bitter Lake NWR about dusk. I immediately hear the bugles of hundreds of Sandhills gathered on the far side of the pond. I was disappointed, afraid that I had missed the fly-in. But as I took photographs, I heard another flock coming in from the west. They flew straight overhead, dropping in altitude to land—kicking their feet outward to make space. Over the next few minutes, more and more birds arrived, adding to the controlled mayhem of the evening roost.

I was surprised that I was the only photographer there that day. I’ve been to see the Sandhill Cranes at the Bosque del Apache National Wildlife Refuge several times. Nearly due west and over the Capitan Mountains, the Bosque del Apache NWR is located on the Rio Grande and is a mecca for wildlife photographers. You stand tripod to tripod, vying for that “pristine nature” shot. But here, at the Bitter Lake NWR, I’m alone.

What I didn’t realize was that I saw something quite extraordinary. There are two subspecies of Sandhill Cranes that overwinter in New Mexico. The Greater Sandhill Crane (Grus canadensis tabida) spends the winter on the Rio Grande at the Bosque del Apache NWR. The Lesser Sandhill Crane (Grus canadensis canadensis) congregates at the Bitter Lake NWR on the Pecos River.

In the spring, the Greater Sandhill Cranes migrate to their breeding grounds in the Rocky Mountain region while the Lessers keep flying northwest, headed for western Alaska and Siberia.


During the day, Sandhill Cranes forage in tilled fields.

Sandhill Cranes Forage for Waste Grains and Bugs in Farm Fields

I watch the Sandhill Cranes take off at sunrise, flying south along the river. “Where do they go?” I asked Bill Flynt, the Visitor Center volunteer. “Head out the Old Dexter Highway,” he told me. “You’ll find them in the farm fields out there.”

I followed the birds south and, just as predicted, found them feeding in a tilled field. Sandhill Cranes feed on seeds, grains, grasshoppers, and pillbugs. I suspect that before the conversion of grasslands to farm fields and desert scrubland, the Sandhills lived primarily on grass seeds and grasshoppers. But these days, they’re dependent on domestic crops such as waste grain or corn left in the fields after harvesting.  They’ll also eat sorghum and sprouting alfalfa which can be a problem for the farmers.

As the local dairy industry grows, the traditional corn and grain crops are replaced by alfalfa, causing a decline in the overwintering populations of Lesser Sandhill Cranes at the Bitter Lake NWR. Refuge scientists believe that the birds are simply moving on as they deplete their local food resources.

Black silhouettes against the evening sky, Sandhill Cranes return for the night.

The Evening Fly-In

My last evening at the refuge, I watch as the Sandhill Cranes begin to fly in. Their loud bugles can be heard for miles. Sometimes I hear them coming long before I can spot them in the sky. This time, they settle far out in the middle of the ponds. I can see them, I can hear them, but I can’t photograph them. That’s okay. It’s time just to sit and watch this amazing wonder of nature.

Also posted in Birds, Chihuahuan Desert Tagged , , |

Ghosts of the Past: Marine Fish on Mimbres Pottery

Porpoise on Mimbres Bowl from the  Deming Luna Mimbres Museum, New Mexico

In the far southwestern corner of New Mexico is a treasure. The Deming Luna Mimbres Museum, housed in the 1916 Armory Building, has collections that include a lot of just about everything. Who knew someone collected buttonhooks and that they could be so interesting? This is the thing about the museum: it’s easy to get distracted.

I visited on a windy, cold, spring day last week with pretty much one goal in mind. I’d heard about their collection of Mimbres artifacts and, as an archeologist, I just couldn’t resist an exhibit like that. I got a bit lost in the doll collection (there wasn’t a way out), wandered past cabinets of porcelain and fine china, meandered down a narrow hall, and then took a left into a room of wonders. Glass cases held ceramic bowls, pots, and bean jars of all shapes and sizes, trays of tiny beads, arrowpoints, bone tools, and fragile cord used for snare traps. I made the rounds, once, twice, and then just stood there, listening to the stories whispered by the pots.

The Mimbres Room, Deming Luna Mimbres Museum, New Mexico

The Mimbres people lived in the Mimbres River valley of southwestern New Mexico. For about 200 years (between AD 950 and 1150) they produced distinctive black-on-white pottery that told the story of their lives—men setting snares and carrying rabbit sticks, women giving birth, and people swimming with a school of fish. Many of the bowls have a single animal carefully painted on the bottom: a frog, bird, pronghorn antelope, or fish.

At first, you think that the animals are simply abstractions, the essence of the animal. But when you look closer, you begin to notice details and you eventually realize that the little fat bird with the tear-drop shaped circle around its eye must be a Montezuma Quail. Which is interesting, because Montezuma Quail don’t occur in that region today. But neither do the fish.

Quail BowlMontezuma Quail

Stephen Jett, a geographer from the University of California, Davis and his colleague Peter Moyle, a fisheries biologist, got interested in the fish represented on Mimbres pots and wrote a paper titled “The Exotic Origins of Fishes Depicted on Prehistoric Mimbres Pottery from New Mexico” (American Antiquities 51(4), 1986, pp 688-720).

About 11% of the animals shown on Mimbres pots are fishes and, as early as the 1950s, researchers noted in passing that many of the fish weren’t what you’d find in the Mimbres River. In fact, they kind of look like something you’d see in the ocean. But as any geographer will tell you, southwestern New Mexico is a long way from the ocean. A very long way away.

Jett funneled every fish image that he could find to Moyle and asked a simple question: What do you think this is? Surprisingly, Jett and Moyle discovered that they could identify many of the fish and that the majority of the fish species painted on Mimbres pots were marine in origin. Jacks, giant jewfish, snappers, grunts, and the distinctive long-nosed butterfly fish were carefully painted by the Mimbres. The Pacific razorfish—with its distinctive “unicorn” fin—is clearly depicted along with tiny blennies, and giant parrotfish.


Of course, the million dollar question is “How in the world did the Mimbres people know what long-nosed butterfly fish and Pacific razorfish looked like?” But before we answer that question, there’s more you should know.

The Mimbres were apparently fascinated by the ocean. Dozens of clam shell bracelets and hundreds of tiny shell beads fill the trays and cases of the Mimbres rooms at the Deming Luna Mimbres Museum. Thousands of shell items—from at least 11 genera of seashells—have been recovered from Mimbres archeological sites in the region.

Ancient seashells found in a Mimbres site in southern New Mexico.

Conventional wisdom is that all of the shell jewelry originally came from the Hohokam, a contemporary cultural group that lived in south-central Arizona and were believed to control the shell trade. They obtained their raw materials from the Gulf of California and the Pacific coast, ground the shell down to create bracelets, tinklers, pendants, and beads, and then traded them to the Anasazi to the north and the Mimbres to the east.

But Jett and Moyle weren’t quite so quick to accept conventional wisdom. The fish on the pots, they say, indicate that the Mimbreños were very familiar with the ocean and were most likely active participants in shell collecting and transportation. By looking at the species of fish and the types of shell, they concluded that the Mimbres people were making trips to the Gulf of California and specifically, the area around Guaymas, Mexico. Near Guaymas both the reefs necessary for the fish species depicted on the pots and the sandy beaches where the shells could be collected are found.

To the modern human, the thought of walking 1000 miles or so to the coast and back is a bit daunting. But to the Mimbreños? Probably not so much. A trip of that distance would only take a couple of months by foot and there were undoubtedly villages (and trade opportunities) along the way. The marine archeologist in me also has to wonder if they used canoes or some type of water transportation to speed up the journey (although I couldn’t find any images of boats on the pottery I saw).

Because there’s little evidence that the Mimbres people either traded their pottery or imported pottery from other places, they must have painted their fish pots when they returned home. Did they sketch the different types of fish on pieces of bark and take them back to show the potters? Or did they memorize details to paint later?

The pots in the museum whisper to me, but they keep some secrets to themselves.

Deming Luna Mimbres Museum | 301 S. Silver Ave., Deming, New Mexico | 575.546.2382 |


Jett, S.C. & P.B. Moyle. 1986. The exotic origins of fishes depicted on prehistoric Mimbres pottery from New Mexico. American Antiquities 51(4):688-720.

Parks-Barrett, M.S. 2001. Prehistoric Jewelry of the NAN Ranch Ruin (LA15049), Grant County, New Mexico. Master’s thesis, Department of Anthropology, Texas A&M University.

Images from the collections of the Deming Luna Mimbres Museum.

Also posted in Animals, Archeology, Chihuahuan Desert, Fish Tagged , , , |